JP7538155B2 - Novel polymerizable liquid crystals with a quinoxaline-hydrazone core - Google Patents

Description

The present invention relates to novel polymerizable anisotropic liquid crystal (LCP) compounds having a quinoxaline-hydrazone core, compositions comprising such LCP compounds, and optical films comprising such LCP compounds or compositions. Optical films comprising the LCPs of the present invention exhibited reverse retardation patterns of polarized light over a wide wavelength range. Finally, the present invention relates to optically anisotropic products comprising such LCP compounds or comprising optical films comprising such LCP compounds, such as, for example, flat displays, televisions, smartphones, tablets, etc.

Optical films (LCP films) prepared from curable LCP compounds are well known to those skilled in the art and are used in the preparation of optical devices. An example of an optical film is a retardation film or polarizer. A retardation film is a type of optical element that changes the polarization state of light passing through it. When light passes through a retardation film, the polarization direction of the light changes due to birefringence and the thickness of the film. A quarter-wave retardation plate converts linearly polarized light into circularly polarized light, and a half-wave retardation plate converts the vibration plane of linearly polarized light by 90°. Such retardation films can achieve the conversion of a specific monochromatic light so that λ/4 or λ/2 retardation occurs. However, known retardation films have the disadvantage that the polarized light passing through them is converted into colored polarized light. Also, for polarized white light, a polarization state distribution corresponding to each wavelength occurs. Therefore, it is impossible to achieve exact λ/4 or λ/2 retardation over the entire wavelength band. To improve such disadvantages, it is necessary to develop a retarder film with a larger wavelength dispersion at longer wavelengths than at shorter wavelengths. Another problem in preparing retardation films, also known as retarders, is preparing high-performance films with small amounts of material.

Therefore, there is a need for new LCP compounds that can be used to prepare such optical films, which significantly reduce the aforementioned disadvantages. The present invention addresses that need.

Although several anisotropic LCP compounds are known in the art, there remains a need to develop new LCP compounds with improved uniform conversion of polarized light over a wider range of wavelengths. Some examples of such anisotropic LCP compounds are disclosed in WO2012/147904, WO2016/104317, WO2017/043437 and JP2016/128403.

LCP films are generally produced by methods well known to those skilled in the art. It involves coating an organic solution of a crosslinkable LCP or LCP mixture onto a substrate with an alignment layer or onto a substrate previously treated by a rubbing method. Alternatively, other aligning methods for liquid crystals may be used. The organic solvent is subsequently removed to give a highly oriented, solvent-free LCP layer, which is then crosslinked to fix the ordered structure of liquid crystal properties. The desired optical performance of such films crucially depends on several physical parameters that the anisotropic LCP material must simultaneously satisfy: a low melting point or a low tendency to crystallize when cooled below the melting point (supercooling), good solubility in organic solvents, good miscibility with other LCPs, good aligning properties in the alignment layer, and the ability to form essentially tilted domains and tunable tilts from the substrate plane without disclinations. Tilted domains are regions in the LCP film where the long axes of the LCP molecules form tilt angles from the substrate plane of the same size and opposite directions. Disclinations are the boundaries between adjacent tilt domains where LCP molecules with opposite tilt angles are in close proximity. These tilt domains and disclinations cause both disruptions to the uniform appearance of the film and inhomogeneous optical performance.

SUMMARY OF THEINVENTION It is a first object of the present invention to provide anisotropic LCP compounds described by formula (I), as well as compositions comprising at least one said compound and at least one additive and/or solvent.

A further object of the present invention is to provide an optical film comprising at least one of said anisotropic LCP compounds and a method for preparing the same, the use of said optical film as a retardation film to achieve uniform transformation of polarized light, and a device comprising said optical film and a method for manufacturing the same.

FIG. 1 shows the wavelength dispersion of birefringence for Examples 1, 2, 2B and 2D. FIG. 2 shows the retardation dispersion of the film of Example 6.

DETAILED DESCRIPTION OF THE PRESENT EMBODIMENT A first aspect of the present invention provides compounds of formula (I):

In the compounds of formula (I), R ₁ , R ₂ and R ₃ are each independently selected from the group consisting of hydrogen, C ₁ -C ₁₂ straight or branched alkyl chain, C ₃ -C ₁₂ alkenyl, C ₁ -C ₁₂ alkoxy, C ₃ -C ₁₂ alkenyloxy, -(CH ₂ ) _m -C(CH ₃ ) ₃ , NO ₂ , CN, COR, -COOR, -OCOR, -CONR'R, -NR'COR, OCOOR, -OCONR'R, -NR'COOR, -F, -Cl, -CF ₃ and -OCF ₃ ;
Where:
m is an integer from 0 to 12;
R is selected from the group consisting of hydrogen, a C _1-18 alkyl group, a C _3-18 alkenyl group having a double bond at position 3 or higher, -(CH ₂ ) _p -C-(CF ₃ ) ₃ , CN, and an unsubstituted or substituted phenyl ring, where the substituents on the phenyl ring are selected from the group consisting of a C ₁ -C ₆ straight or branched alkyl chain, a C ₁ -C ₆ alkoxy, -C-(CH ₃ ) ₃ , halogen, -CF ₃ , NO ₂ , CN, COR''', -COOR'''', -OCOR'''', -CONR''R'''', -NR''COR'''', OCOOR'''', -OCONR''R'''', -NR''COOR'''', -F, -Cl, -CF ₃ , and -OCF ₃ ;
Where:
R″ is selected from the group consisting of hydrogen, lower alkyl, and lower alkenyl;
R''' is selected from the group consisting of hydrogen, a _C1-18 alkyl group, and a _C3-18 alkenyl group having a double bond at the 3rd or higher position;
p is an integer from 0 to 12;
R' is selected from the group consisting of hydrogen, lower alkyl, lower alkenyl, and lower alkoxy; and
n is 0, 1, 2, or 3.

Preferably, R ₁ , R ₂ and R ₃ are each independently selected from the group consisting of hydrogen, lower alkyl, lower alkenyl, lower alkoxy, lower alkenyloxy, -F and -CF ₃ .

Most preferably, R ₁ , R ₂ and R ₃ are independently selected from the group consisting of hydrogen, methyl, methoxy, -F, -C-(CH ₃ ) ₃ and -CF ₃ .

Y is selected from the group consisting of H or a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms.

Z is selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, where one or more carbon atoms may be replaced by -O-, -COO-, -OCO-, -OOC-, -O(CO)O-, -N-, -NR ^a -, -CON-, -CO-R ^b , -NH-R ^c , where R ^a is a C ₁ to C ₁₂ alkyl group, R ^b and R ^c are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or an organic group having 2 to 30 carbon atoms containing at least one aromatic ring, or a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms.

Preferably, Z is selected from the group consisting of hydrogen and substituted or unsubstituted alkyl groups having 1 to 12 carbon atoms.

で示される基からなる群より選択される（ただし、環Ｃ又はＤの少なくとも一方は、芳香環を含有する）。 Rings C and D are each independently phenyl, biphenyl, naphthyl, cycloalkyl, preferably cyclohexyl, bicycloalkyl, preferably bicyclohexyl, the following formula:

(with the proviso that at least one of rings C and D contains an aromatic ring).

Preferably, rings C and D are each independently phenyl or cyclohexyl, and most preferably, both rings C and D are phenyl rings.

Ring E is selected from the group consisting of phenyl, biphenyl and naphthyl.

Preferably, ring E is a phenyl ring.

で示される基により表される。 The substituents X ₁ and X ₂ are, independently of one another, selected from the group consisting of hydrogen, a C ₁ -C ₁₂ substituted or unsubstituted linear or branched alkyl chain, a C ₃ -C ₁₂ substituted or unsubstituted linear or branched alkenyl chain and a C ₁ -C ₁₂ alkoxy, in which one or more carbon atoms may be replaced by -O-, -COO-, -OCO-, -OOC-, -O(CO)O-, -N-, -NR a -, -CON-, in which R a is a C 1 -C 12 alkyl group; or the substituents X 1 and X 2 are, independently of one another, selected from the group consisting of hydrogen, a C 1 -C 12 substituted or unsubstituted linear or branched alkyl chain, a C 3 -C 12 substituted or unsubstituted linear or branched alkenyl chain and a C ₁ -C 12 alkoxy, in which one or _more carbon atoms may be replaced by -O-, ^-COO- , -OCO-, -OOC-, -O(CO)O-, -N-, -NR a -, -CON-, in which R ^a is a C ₁ -C ₁₂ alkyl group;

The compound is represented by the group represented by the formula:

In the group of formula (II), n is an integer from 0 to 24, wherein one or more carbon atoms may be replaced by -O-, -COO-, -OCO-, -OOC-, -O(CO)O-, -N-, -NR ^a -, -CON-, where R ^a is a C ₁ to C ₁₂ alkyl group.

The substituent PG in the radical of formula (II) represents a polymerizable group selected from the group consisting of CH ₂ ═C(Ph)-, CH ₂ ═CW-COO-, CH ₂ ═CH-COO-Ph-, CH ₂ ═CW-CO-NH-, CH ₂ ═CH-O-, CH ₂ ═CH-OOC-, Ph-CH═CH-, CH ₂ ═CH-Ph-, CH ₂ ═CH-Ph-O-, R ^b -Ph-CH═CH-COO-, R ^b -OOC-CH═CH-Ph-O- and 2-W-epoxyethyl; where W represents H, Cl, Ph or lower alkyl and R ^b represents lower alkyl, with the proviso that R ^b , when attached to the phenylene group (-Ph-), may also represent hydrogen or lower alkoxy. Preferably, PG represents an acrylate or methacrylate group.

When rings C and D are, independently of one another, cyclohexyl or contain cyclohexyl, preferably the substituents _X1 and _X2 are selected from the group consisting of hydrogen, _C1 - _C12 substituted or unsubstituted linear or branched alkyl chains, _C3 - _C12 substituted or unsubstituted linear or branched alkenyl chains and _C1 - _C12 alkoxy.

［式中、ｎは、上記と同じ意味を有する］で示される基か、又はそれらの対応するメタクリラートから選択される。 Preferably, when rings C or D are, independently of one another, aromatic rings or contain an aromatic ring, more preferably when C or D are, independently of one another, phenyl rings or contain a phenyl ring, the group of formula (II) is

wherein n has the same meaning as above, or the corresponding methacrylates thereof.

The term "lower alkyl" should be understood to include C _1-6 achiral branched or straight chain alkyl groups. Examples of lower alkyl groups that may be present in the compounds of the invention include methyl, ethyl, propyl, butyl, pentyl, hexyl, and the like.

The term "lower alkenyl" should be understood to include C _3-6 achiral branched or straight chain alkenyl groups in which the double bond is at position 2 or higher. Examples of lower alkenyl groups which may be present in the compounds of the invention include 2-propenyl, 3-butenyl, 3-isopentenyl, 4-pentenyl, 5-hexenyl, 4-isohexenyl, and the like.

The term "lower alkoxy" should be understood to include C _1-6 achiral branched or straight chain alkoxy groups. Examples of lower alkoxy groups that may be present in the compounds of the invention include methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, and the like.

The term "lower alkenyloxy" should be understood to include C _3-6 achiral branched or straight chain alkenyloxy groups in which the double bond is at position 2 or higher. Examples of lower alkenyloxy groups which may be present in the compounds of the invention include 2-propenyloxy, 3-butenyloxy, 4-pentenyloxy, 5-hexenyloxy, and the like.

The polymerizable anisotropic LCP compounds of the present invention can be readily prepared using procedures well known to those skilled in the art, a few non-limiting procedures being provided in the examples.

The starting materials are commercially available or can be readily prepared and are well known to those skilled in the art.

Polymerizable anisotropic LCP compound material as used in the context of this application shall mean a liquid crystal material comprising liquid crystal monomers and/or liquid crystal oligomers and/or liquid crystal polymers and/or crosslinked liquid crystals. When the liquid crystal material comprises liquid crystal monomers, such monomers can typically be polymerized after the LCP material is rendered anisotropic, for example, due to contact with an alignment layer or by rubbing. Polymerization can be initiated by heat treatment and/or exposure to actinic radiation (preferably including UV light). Anisotropic LCP materials may comprise only a single type of liquid crystal compound, but may also comprise additional polymerizable and/or non-polymerizable compounds, where not all compounds need to be liquid crystal compounds. In the case of optical films, the LCP monomers are applied on top of a photoalignment layer or on top of a rubbed surface. After the alignment information of the photoalignment layer or of the rubbed surface is transferred to the LCP monomers, the monomers are polymerized and/or crosslinked to solidify the LCP material. It is understood that the polymerized or crosslinked polymer of the present invention may contain only the anisotropic LCP compound of formula (I) alone, in which case the polymer is a homopolymer, or the polymerized or crosslinked polymer may contain further different monomers, in which case the polymer is a copolymer. The further different monomers may or may not have LCP properties.

The anisotropic LCP compounds of the present invention overcome the disadvantages previously described for prior art LCP compounds. Furthermore, the anisotropic LCP compounds of the present invention have excellent solubility and low temperature processability.

A further object of the present invention relates to a composition comprising an anisotropic LCP compound described by formula (I) and at least one additive. The additive can be selected from: antioxidants, initiators such as photoinitiators, accelerators, dyes, inhibitors, activators, fillers, chain transfer inhibitors, pigments, antistatic agents, flame retardants, thickeners, thixotropic agents, surfactants, viscosity modifiers, extender oils, plasticizers, tackifiers, catalysts, sensitizers, stabilizers, leveling agents, dispersants, polymeric binders and/or monomeric compounds that can be converted into polymeric binders by polymerization, or in the case of emulsion coatings and printing inks, dispersing aids, hydrophobizing agents, adhesives, flow improvers, defoamers, degassing agents, diluents, auxiliaries, colorants, dyes and pigments, hardening inhibitors, chiral additives, isotropic or anisotropic fluorescent and/or non-fluorescent dyes, in particular dichroic dyes. Solvents that can be used in the preparation of such liquid crystal compositions include, but are not limited to, acetone, cyclopentanone (CP), cyclohexanone (CH), methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), N-ethylpyrrolidone, N-vinylpyrrolidone, N,N-dimethylacetamide, (AN), tetrahydrofuran (THF), 1,3-dioxolane (DXG), ethylene glycol, dipropylene glycol, butyl carbitol, ethyl carbitol acetate, dipropylene glycol monomethyl ether, ethyl acetate (EA), 1-methoxy-2-propanol acetate (MPA), γ-butyrolactone (BL), propylene glycol monoacetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, and dimethyl sulfoxide (DMSO). The most preferred solvents are cyclopentanone (CP), cyclohexanone (CH), methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), ethyl acetate (EA), 1-methoxy-2-propanol acetate (MPA), 1,3-dioxolane (DXG), and dimethyl sulfoxide (DMSO).

A further preferred object of the present invention relates to a composition comprising an anisotropic LCP compound of formula (I), an LCP mixture, and at least one solvent selected from cyclohexanone, toluene and cyclopentanone; and/or an additive.

A further preferred embodiment of the present invention is a composition, an LCP mixture, comprising an anisotropic compound of formula (I), which preferably has a shelf life stability of more than 3 months without crystallization.

The present invention relates to an optical film comprising at least one of the anisotropic LCP compounds or compositions of the present invention. One example of an optical film is an anti-reflective film produced by combining the optical film of the present invention with a polarizer.

The anisotropic LCP compound or a composition comprising an anisotropic LCP compound can be applied onto a support. The support can be rigid or flexible and can have any form or geometry. In principle, it can be made of any material. Preferably, the support comprises plastic, glass or metal, or is a silicon wafer. If the support is flexible, it is preferred that the support is a plastic or metal foil. Preferably, the surface of the support is flat. In some applications, the support may include topographical surface structures, such as microstructures like microlenses or microprisms, or structures that exhibit abrupt changes in geometry, such as rectangular structures. Preferably, the support is transparent. The support may also be subjected to a treatment before coating with the anisotropic LCP compound of the present invention.

The support may move during deposition of the anisotropic LCP compound or a composition comprising an anisotropic LCP compound. For example, a layer of an LCP mixture may be produced in a continuous roll-to-roll process by depositing the material composition onto a moving flexible foil, preferably plastic or metal. The resulting film may then be wound into a roll together with the support foil, or the film may be released from the support and then wound as a free-standing film without the support.

The support may have additional layers such as photoalignment layers, organic layers, insulating layers or metal layers. The layers may have different functions, for example an organic layer may be coated as a primer layer to enhance the compatibility of the coated material with the support. The metal layer may be used as an electrode, for example when used in an electro-optical device such as a display, or may have the function of a reflector. The support may also be an optical element or device with a specific function, such as a substrate for an LCD, which may include thin film transistors, electrodes or color filters. In another example, the support is a device that includes an OLED layer structure. The support may also be a polarizer, such as a polarizing film or sheet polarizer, a reflective polarizer such as the commercially available Vikuity™ DBEF film.

In the context of the present invention, a "photoalignment layer" is made from a material that is a photoalignable substance in which anisotropic properties can be induced upon exposure to aligning light. Furthermore, the term "photoalignment layer" refers to a layer that is aligned by exposure to aligning light. In the present case, the induced anisotropy must be such that it provides alignment capabilities to an adjacent layer that contains, for example, an anisotropic LCP compound of formula (I). The term "alignment direction" refers to the preferred direction that is induced in the adjacent layer, for example, the alignment direction is the direction in which the LCP compound will align.

The photoalignable material incorporates photoalignable substructures that can develop a preferred direction and produce anisotropic properties upon exposure to aligning light. Such photoalignable substructures preferably have anisotropic absorption properties. Typically, such substructures exhibit absorption in the wavelength range of 230-500 nm. Preferably, the photoalignable substructures exhibit absorption of light in the wavelength range of 300-450 nm, and more preferably, in the wavelength range of 310-380 nm.

Preferably, the photoalignable substructure has a carbon-carbon, carbon-nitrogen, or nitrogen-nitrogen double bond.

For example, the photo-orientable moieties are substituted or unsubstituted azo dyes, anthraquinones, coumarins, melissyanins, 2-phenylazothiazoles, 2-phenylazobenzothiazoles, stilbenes, cyanostilbenes, fluorostilbenes, cinnamonitriles, chalcones, cinnamates, cyanocinnamates, stilbazoliums, 1,4-bis(2-phenylethylenyl)benzenes, 4,4'-bis(arylazo)stilbenes, perylenes, 4,8-diamino-1,5-naphthoquinone dyes, aryloxycarboxylic acid derivatives, aryl esters, N-arylamides, polyimides, diaryl ketones having ketone moieties or ketone derivatives bonded to two aromatic rings (e.g., substituted benzophenones, benzophenone imines, phenylhydrazones, and semicarbazones).

Methods for preparing the anisotropic absorbing materials listed above are well known, as shown, for example, in U.S. Pat. No. 4,565,424 to Hoffman et al., U.S. Pat. No. 4,401,369 to Jones et al., U.S. Pat. No. 4,122,027 to Cole, Jr. et al., U.S. Pat. No. 4,667,020 to Etzbach et al., and U.S. Pat. No. 5,389,285 to Shannon et al.

Preferably, the photoalignable moiety includes an arylazo, a poly(arylazo), a stilbene, a cyanostilbene, a cinnamate, or a chalcone.

The photoalignable material may in particular be a monomer, oligomer or polymer. The photoalignable moieties may be covalently bonded, for example, in the main chain or in the side chains of a polymer or oligomer, or they may be part of a monomer or other compound that is not polymerizable. The photoalignable material may furthermore be a copolymer comprising different types of photoalignable moieties, or a copolymer comprising side chains with and without photoalignable moieties.

Polymers mean, for example, polyacrylates, polymethacrylates, polyimides, polyurethanes, polyamic acids, polymaleimides, poly-2-chloroacrylates, poly-2-phenylacrylates; unsubstituted or C ₁ -C ₆ alkyl substituted polyacrylamides, polymethacrylamides, poly-2-chloroacrylamides, poly-2-phenylacrylamides, polyethers, polyvinyl ethers, polyesters, polyvinyl esters, polystyrene derivatives, polysiloxanes, linear or branched alkyl esters of polyacrylic or polymethacrylic acid; polyphenoxyalkylacrylates, polyphenoxyalkylmethacrylates, polyphenylalkylmethacrylates with alkyl residues of 1 to 20 carbon atoms; polyacrylonitriles, polymethacrylonitriles, cycloolefin polymers, polystyrene, poly-4-methylstyrene or mixtures thereof.

The photoalignable material may also include photosensitizers, such as ketocoumarins and benzophenones.

Further preferred photoalignable monomers, oligomers or polymers are described in U.S. Pat. Nos. 5,539,074, 6,201,087, 6,107,427, 6,632,909 and 7,959,990.

Alignment of LCPs can be achieved by other known means for aligning liquid crystals. For example, the support may have an aligning surface, meaning that the surface has the ability to align liquid crystals. The support may already provide alignment without further processing. For example, if a plastic substrate is used as the support, it may provide alignment on the surface due to the manufacturing method, e.g., extrusion or stretching of the substrate. It is also possible to brush the support or imprint a directional microstructure to create alignment capabilities.

The steps of polymerizing the LCP compound and exposing it to the aligning light may be in any order. Polymerization may be initiated before or after exposure to the aligning light. Alternatively, polymerization and exposure may occur simultaneously.

A further embodiment of the present invention relates to a method for producing an optical film comprising an anisotropic compound of formula (I) of the present invention, an LCP blend or an LCP network, preferably by exposure to aligning light with an energy of <200 mJ, more preferably <150 mJ and more preferably <100 mJ.

The LCP mixture can be applied to the substrate by any suitable method, such as extrusion, casting, molding, 2D or 3D printing or coating. Suitable coating methods are, for example, spin coating, blade coating, knife coating, kiss roll coating, die coating, dipping, brushing, casting with a bar, roller coating, flow coating, wire coating, spray coating, dip coating, curtain coating, air knife coating, reverse roll coating, gravure coating, metering rod (Meyer bar) coating, slot die (extrusion) coating, roller coating, flexo coating. Suitable printing methods include letterpress printing such as silk screen printing, flexography, jet printing, intaglio printing such as direct gravure printing or offset gravure printing, lithography printing such as offset printing, or stencil printing such as screen printing.

A further embodiment of the present invention is an optical film comprising an anisotropic compound of formula (I) of the present invention, or an LCP mixture, or an LCP network. Preferably, the optical film comprises an aligned anisotropic compound of formula (I), or an LCP mixture, or an LCP network. More preferably, the alignment quality is uniform and free of tilted domains.

Further preferred are optical films comprising the LCP of the present invention that exhibit a reverse retardation pattern of polarized light over a wide wavelength band.The optical films of the present invention preferably have birefringence with reverse wavelength dispersion: _Re450 / _Re550 is less than 0.88, preferably Re450/ _Re550 is <0.85; while _Re650 / _Re550 is greater than 1.01, preferably _Re650 / _Re550 is >1.03 ( _Re450 represents the retardation of the film at a wavelength of ₄₅₀ nm, _Re550 represents the retardation of the film at a wavelength of 550 nm, and _Re650 represents the retardation of the film at a wavelength of 650 nm).

The present invention will now be described with reference to the following non-limiting examples. These examples are provided for illustrative purposes only. Variations of these examples that fall within the scope of the invention will be apparent to those of ordinary skill in the art.

The following examples are provided to further illustrate and facilitate understanding of the present invention and are not intended to limit the invention in any way.

Example 1
Synthesis of Compound 1 Synthesis of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-formyl-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl]:
Oxalyl chloride (2.5 mL, 29 mmol) was added dropwise to a solution of 4-(6-acryloyloxy-hex-1-yloxy)benzoic acid (6.98 g, 24 mmol) in 48 mL anhydrous toluene, 4 mg 4-methoxyphenol and 1 mL anhydrous DMF at 45° C. After 2 h, the reaction mixture was cooled to 0° C. and added dropwise to a solution of 2,5-dihydroxybenzaldehyde (1.5 g, 11 mmol) in 40 mL anhydrous DMA and N,N-dimethylcyclohexylamine (7.8 g, 52 mmol) at 0-5° C. The reaction mixture was stirred overnight at ambient temperature. The orange solution was quenched by the addition of 15 mL water, extracted with dichloromethane, washed successively with water, brine, dried over sodium sulfate and concentrated in vacuo. After recrystallization from dichloromethane/methanol, the title compound was obtained as a white solid (4.19 g, 56%).
¹ H NMR (400 MHz, DMSO-d6) δ 10.04 (s, 1H), 8.08 (m, 4H), 7.82 (d,1H), 7.71 (dd, 1H), 7.54 (d, 1H), 7.10 (m, 4H), 6.26 (d, 1H), 6.15 (dd, 1H) ), 5.90 (d, 1H), 4.09 (m, 8H), 1.72 (m, 4H), 1.60 (m, 4H), 1.39 (m, 8H).

Synthesis of 2-hydrazinylquinoxaline:
A microwave reactor was charged with 2-chloroquinoxaline (1.70 g, 15 mmol), hydrazine monohydrate (1.82 mL, 37.5 mmol) in absolute ethanol (15 mL). The mixture was heated to 90 °C for 20 min in a microwave reactor. The reaction mixture was cooled and the precipitate was filtered and washed with hexane to give the title compound as an orange solid (2.07 g, 86%). ¹ H-NMR (400 MHz, DMSO-d6) δ 8.67 (s, 1H), 8.34 (s, 1H), 7.76 (d, J = 8.2 Hz, 1H), 7.52-7.58 (m, 2H), 7.30-7.34 (m, 1H), 4.43 (s, 2H).

Synthesis of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-3-[(E)-(quinoxalin-2-ylhydrazono)methyl]phenyl] (Compound 1)
(±)10-Camphorsulfonic acid (23.2 mg, 0.1 mmol) was added to a solution of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-formyl-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (0.69 g, 1.0 mmol) and 2-hydrazinylquinoxaline (0.19 g, 1.2 mmol) in 10 mL of anhydrous tetrahydrofuran under nitrogen atmosphere. The resulting solution was stirred at ambient temperature for 3 h. After completion of the reaction, the reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with dichloromethane. The organic phase was washed with brine, dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure. After recrystallization from dichloromethane/hexane, the title compound was obtained as a yellow solid (0.67 g, 81%).
¹ H NMR (400 MHz, CDCl ₃ ) δ 9.11 (s, 1H), 8.63 (s, 1H), 8.17-8.20 (m, 4H), 7.97 (d, J = 8.2 Hz, 1H), 7.92-7.94 (m, 2H), 7.59-7.68 (m, 2H), 7 .46-7.52 (m, 1H), 7.29 (s, 2H), 6.98-7.02 (m, 4H), 6.38-6.43 (m, 2H), 6.10-6.17 (m, 2H), 5.81-5.84 (m, 2H), 4.19 (t, J = 6.6 Hz, 4H), 4.06-4.11 (m, 4H), 1.83-1.90 (m, 4H), 1.71-1.78 (m, 4H), 1.45-1.53 (m, 8H); MALDI-TOF (CHCA) 851.33 (M ⁺ +Na).

Example 2
Synthesis of compound 2:
Synthesis of tert-butyl N-(quinoxalin-2-ylamino)carbamate:
A solution of di-tert-butyl dicarbonate (3.9 g, 18 mmol) in anhydrous THF (9 mL) was added to a solution of 2-hydrazinylquinoxaline (2.4 g, 15 mmol) in anhydrous THF (30 mL). The reaction mixture was stirred at 50 °C for 2 h. The reaction mixture was cooled to room temperature, quenched with a saturated aqueous solution of sodium bicarbonate, and extracted twice with a 1:2 mixture of ethyl acetate and hexane. The organic layer was washed with brine, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure to give the title compound as a brown solid (4.11 g, quantitative).
¹ H NMR (400 MHz, DMSO-d6) δ 9.27 (s, 1H), 9.02 (s, 1H), 8.35 (s, 1H), 7.84 (d, J = 8.2 Hz, 1H), 7.60-7.63 (m, 2H), 7.41-7.45 (m, 1H), (s, 9H).

Synthesis of tert-butyl N-[methyl(quinoxalin-2-yl)amino]carbamate:
Iodomethane (0.4 mL, 6.3 mmol) was added to a solution of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-formyl-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (1.5 g, 5.8 mmol) in anhydrous DMF (10 mL) at 0° C. The reaction mixture was stirred at ambient temperature for 3 h. The reaction mixture was quenched with water and extracted twice with a 1:2 mixture of ethyl acetate and hexanes. The organic layer was washed with water and brine, dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure. The residue was purified by flash column chromatography on silica gel using a 1:2 mixture of ethyl acetate/hexanes to give the title compound as a red oil (0.46 g, 21%). ¹ H NMR (400 MHz, DMSO-d6) δ 9.72 (s, 1H), 8.54 (s, 1H), 7.87 (d, J = 7.8 Hz, 1H), 7.68-7.71 (m, 1H), 7.63-7.67 (m, 1H), 7.45-7.49 (m, 1H), 3.29 (s, 3H), 1.44 (s, 9H).

Synthesis of 1-methyl-1-quinoxalin-2-yl-hydrazine:
Trifluoroacetic acid (TFA) (3 mL) was added to a solution of tert-butyl N-[methyl(quinoxalin-2-yl)amino]carbamate (0.43 g, 1.6 mmol) in dichloromethane (3 mL). The reaction mixture was stirred at ambient temperature for 3 h. The solvent was removed under reduced pressure and the residue was dissolved in dichloromethane, washed with a saturated aqueous solution of sodium bicarbonate and brine, dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure to give the title compound as a yellow solid (0.25 g, 93%). ¹ H NMR (400 MHz, DMSO-d6) δ 9.02 (s, 1H), 7.90 (dd, J = 8.2, 1.4 Hz, 1H), 7.69 (dd, J = 8.2, 0.9 Hz, 1H), 7.55-7.59 (m, 1H), 7.37-7.42 (m, 1H) , 4.14 (s, 2H), 3.47 (s, 3H).

Synthesis of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-[(E)-[methyl(quinoxalin-2-yl)hydrazono]methyl]-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (Compound 2)
(±)10-Camphorsulfonic acid (32 mg, 0.14 mmol) was added to a solution of bis[4-(6-acryloyloxyhexyloxy)benzoic acid]2-formyl-1,4-phenylene (0.95 g, 1.4 mmol) and N-methyl-N-(quinoxalin-2-yl)hydrazine (0.25 g, 1.5 mmol) in 14 mL of anhydrous tetrahydrofuran under nitrogen atmosphere. The resulting solution was stirred at ambient temperature for 3 h. After completion of the reaction, the reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with dichloromethane. The organic phase was washed with brine, dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure. After recrystallization from dichloromethane/hexane, the title compound was obtained as a yellow solid (0.92 g, 79%).
¹ H NMR (400 MHz, DMSO-d6) δ 9.44 (s, 1H), 8.12-8.17 (m, 4H), 8.08 (d, J = 2.7 Hz, 1H), 7.93 (s, 1H), 7.89 (d, J = 8.2 Hz, 1H), 7.74-7.77 (m, 1H), 7.66-7.70 (m, 1H), 7.50-7.55 (m, 1H), 7.43 (d, J = 8.7 Hz, 1H), 7.37 (dd, J = 8.7, 2.7 Hz, 1H), 7.12-7.15 (m, 4H), 6.29-6.34 (m, 2H) , 6.14-6.20 (m, 2H), 5.92-5.95 (m, 2H), 4.08-4.13 (m, 8H), 3.63 (s, 3H), 1.76 (s, 4H), 1.60-1.68 (m, 4H), 1.40-1.46 (m, 8H).

Example 2A
Synthesis of compound 2A:
Synthesis of tert-butyl N-[hexyl(quinoxalin-2-yl)amino]carbamate:
A round-bottom flask was charged with tert-butyl N-(quinoxalin-2-ylamino)carbamate (1.36 g, 5 mmol), 1-iodohexane (0.88 mL, 6 mmol), potassium carbonate (1.04 g, 7.5 mmol), and anhydrous DMF (10 mL). The mixture was stirred at 50° C. under nitrogen atmosphere for 18 h. The reaction mixture was cooled to ambient temperature, diluted with a mixture of ethyl acetate/hexane (1/2), washed three times with water and once with brine. The organic layer was dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure. The residue was purified by flash column chromatography on silica gel with ethyl acetate/hexane to give the title compound as a brown oil (443 mg, 26%).
¹ H-NMR (400 MHz, DMSO-d6) δ 9.72 (s, 1H), 8.46 (s, 1H), 7.85 (d, J = 7.8 Hz, 1H), 7.61-7.67 (m, 2H), 7.43-7.47 (m, 1H), 1.57-1.64 (m, 2H) , 1.45 (s, 9H), 1.24-1.33 (m, 8H), 0.83-0.87 (m, 3H)

Synthesis of 1-hexyl-1-quinoxalin-2-yl-hydrazine:
Trifluoroacetic acid (TFA) (2.5 mL) was added to a solution of tert-butyl N-[hexyl(quinoxalin-2-yl)amino]carbamate (0.44 g, 1.3 mmol) in dichloromethane (2.5 mL). The reaction mixture was stirred at ambient temperature for 19 h. The solvent was removed under reduced pressure and the residue was dissolved in ethyl acetate, washed with a saturated aqueous solution of sodium bicarbonate and brine, dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure to give the title compound as a beige oil (0.31 g, quantitative).
¹ H-NMR (400 MHz, DMSO-d6) δ 9.04 (s, 1H), 7.76 (d, J = 7.8 Hz, 1H), 7.49-7.55 (m, 2H), 7.29-7.33 (m, 1H), 4.86 (s, 2H), 3.74-3.77 (m, 2H) , 1.64-1.71 (m, 2H), 1.23-1.35 (m, 6H), 0.83-0.87 (m, 3H)

Synthesis of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-[(E)-[hexyl(quinoxalin-2-yl)hydrazono]methyl]-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (Compound 2A)
(±) 10-Camphorsulfonic acid (26 mg, 0.11 mmol) was added to a solution of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-[(E)-[methyl(quinoxalin-2-yl)hydrazono]methyl]-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (0.74 g, 1.1 mmol) and 1-hexyl-1-quinoxalin-2-yl-hydrazine (0.31 g, 1.3 mmol) in anhydrous tetrahydrofuran (10 mL) under nitrogen atmosphere. The resulting solution was stirred at ambient temperature for 18 hours. After completion of the reaction, the reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with dichloromethane. The organic phase was washed with brine, dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure. After recrystallization from dichloromethane/hexanes, the title compound was obtained as a pale yellow solid (0.70 g, 72%).
¹ H-NMR (400 MHz, DMSO-d6) δ 9.47 (s, 1H), 8.18 (d, J = 9.1 Hz, 2H), 8.13 (d, J = 9.1 Hz, 2H), 8.10 (d, J = 2.7 Hz, 1H), 7.88-7.91 (m, 2H), 3 (dd, J = 8.5, 1.1 Hz, 1H), 7.65-7.69 (m, 1H), 7.50-7.54 (m, 1H), 7.44 (d, J = 8.7 Hz, 1H), 7.38 (dd, J = 8.7, 2.7 Hz, 1H), 7.15 (d, J = 2.7 Hz , 2H), 7.12 (d, J = 3.2 Hz, 2H), 6.32 (dd, J = 17.4, 1.8 Hz, 2H), 6.17 (ddd, J = 17.4, 10.3, 1.1 Hz, 2H), 5.93 (dd, J = 10.5, 1.8 Hz, 2H), 4.24-4.28 (m, 2 H), 4.07-4.13 (m, 8H), 1.72-1.80 (m, 4H), 1.59-1.68 (m, 4H), 1.36-1.50 (m, 10H), 0.95-1.11 (m, 6H), 0.72 (t, J = 7.1 Hz, 3H).

Example 2B
Synthesis of compound 2B:
Synthesis of 4-propylcyclohexanecarboxylic acid (3-formyl-4-hydroxy-phenyl)
To a solution of 2,5-dihydroxybenzaldehyde (1.38 g, 10 mmol), trans-4-propylcyclohexanecarboxylic acid (1.79 g, 10.5 mmol) and 4-dimethylaminopyridine (DMAP) (122 mg, 1 mmol) in anhydrous dichloromethane (20 mL) was added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) (1.94 mL, 11 mmol) slowly. The reaction mixture was stirred at ambient temperature for 22 h. The reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with dichloromethane. The organic phase was washed with brine, dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure. The residue was purified by flash column chromatography on silica gel with ethyl acetate/hexane to give the title compound as a yellow solid (1.31 g, 45%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 10.90 (s, 1H), 9.85 (s, 1H), 7.31 (d, J = 2.7 Hz, 1H), 7.23 (dd, J = 9.1, 2.7 Hz, 1H), 6.99 (d, J = 9.1 Hz, 1H), -2.52 (m, 1H), 2.11-2.15 (m, 2H), 1.86-1.90 (m, 2H), 1.50-1.57 (m, 2H), 1.29-1.39 (m, 3H), 1.17-1.23 (m, 2H), 0.97-1.04 (m, 3H), 0. 87-0.92 (m, 3H)

Synthesis of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [2-formyl-4-(4-propylcyclohexanecarbonyl)oxy-phenyl]:
To a solution of 4-propylcyclohexanecarboxylic acid (3-formyl-4-hydroxy-phenyl) (1.3 g, 4.5 mmol), 4-(6-acryloyloxy-hex-1-yloxy)benzoic acid (1.38 g, 4.70 mmol) and 4-dimethylaminopyridine (DMAP) (55 mg, 0.45 mmol) in anhydrous dichloromethane (9 mL) was added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) (0.87 mL, 4.93 mmol). The reaction mixture was stirred at ambient temperature for 5 h. The reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with ethyl acetate. The organic phase was washed with brine, dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure. The residue was purified by flash column chromatography on silica gel with ethyl acetate/hexane to give the title compound as a beige oil (2.73 g) containing minor impurities, which was used in the next reaction without further purification.

Synthesis of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [2-[(E)-[methyl(quinoxalin-2-yl)hydrazono]methyl]-4-(4-propylcyclohexanecarbonyl)oxy-phenyl] (compound 2B)
(±) 10-Camphorsulfonic acid (105 mg, 0.45 mmol) was added to a solution of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-formyl-4-(4-propylcyclohexanecarbonyl)oxy-phenyl] (2.73 g, 4.5 mmol), 1-methyl-1-quinoxalin-2-yl-hydrazine (0.82 g, 4.7 mmol), and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical (TEMPO-OH) (9 mg, 0.05 mmol) in anhydrous tetrahydrofuran (45 mL) under nitrogen atmosphere. The resulting solution was stirred at ambient temperature for 24 h. The reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with dichloromethane. The organic phase was washed with brine, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure. After recrystallization from dichloromethane/hexanes, the title compound was obtained as a grey solid (1.61 g, 50%).
¹ H-NMR (400 MHz, DMSO-d6) δ 9.39 (s, 1H), 8.14 (d, J = 9.1 Hz, 2H), 7.90-7.92 (m, 2H), 7.85-7.86 (m, 1H), 7.75-7.77 (m, 1H), 7.67-7.71 (m , 1H), 7.52-7.56 (m, 1H), 7.39 (d, J = 8.7 Hz, 1H), 7.20 (dd, J = 8.7, 2.7 Hz, 1H), 7.12 (d, J = 8.7 Hz, 2H), 6.32 (dd, J = 17.2, 1.6 Hz, 1H), 6.17 (dd, J = 17.4, 10.5 Hz, 1H), 5.93 (dd, J = 10.3, 1.6 Hz, 1H), 4.07-4.13 (m, 4H), 3.62 (s, 3H), 2.11-2.15 (m, 2H), 1.72-1.84 (m, 4H), 1.61-1.6 8 (m, 2H), 1.37-1.54 (m, 7H), 1.27-1.35 (m, 3H), 1.16-1.21 (m, 2H), 0.95-1.04 (m, 2H), 0.87 (t, J = 7.1 Hz, 3H)

Example 2C
Synthesis of compound 2C:
Synthesis of 2-[amino(quinoxalin-2-yl)amino]ethanol:
A microwave reaction vessel was charged with 2-chloroquinoxaline (0.82 g, 5 mmol) and 2-hydrazinoethanol (0.85 mL, 12.5 mmol) in absolute EtOH (2.5 mL). The mixture was heated to 90 °C for 10 min in a microwave reactor. The reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with dichloromethane. The organic phase was washed with brine, dried over anhydrous sodium sulfate and the solvent removed under reduced pressure. The residue was washed with hexane to give the title compound as a yellow solid (0.59 g, 58%).
¹ H-NMR (400 MHz, DMSO-d6) δ 9.05 (s, 1H), 7.77 (d, J = 8.2 Hz, 1H), 7.51-7.54 (m, 2H), 7.30-7.34 (m, 1H), 4.91 (s, 2H), 4.79 (t, J = 5.3 Hz, 1H), 3.86 (t, J = 5.9 Hz, 2H), 3.73 (q, J = 5.6 Hz, 2H)

Synthesis of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-[(E)-[2-hydroxyethyl(quinoxalin-2-yl)hydrazono]methyl]-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (Compound 2C)
(±)10-Camphorsulfonic acid (46 mg, 0.2 mmol) was added to a solution of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-formyl-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (1.37 g, 2 mmol), 2-[amino(quinoxalin-2-yl)amino]ethanol (0.43 g, 2.1 mmol), and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical (TEMPO-OH) (3 mg, 0.02 mmol) in anhydrous tetrahydrofuran (20 mL) under nitrogen atmosphere. The resulting solution was stirred at ambient temperature for 23 h. The reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with dichloromethane. The organic phase was washed with brine, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure. After recrystallization from dichloromethane/methanol the title compound was obtained as a yellow solid (1.46 g, 83%).
¹ H-NMR (400 MHz, DMSO-d6) δ 9.42 (s, 1H), 8.26 (s, 1H), 8.12-8.16 (m, 4H), 8.05 (d, J = 2.7 Hz, 1H), 7.89 (d, J = 8.2 Hz, 1H), 7.74 (dd, J = 8. 2, 0.9 Hz, 1H), 7.65-7.69 (m, 1H), 7.50-7.54 (m, 1H), 7.44 (d, J = 8.7 Hz, 1H), 7.37 (dd, J = 8.7, 2.7 Hz, 1H), 7.10-7.15 (m, 4H), 6.32 (dd , J = 17.2, 1.6 Hz, 2H), 6.17 (dd, J = 17.4, 10.1 Hz, 2H), 5.93 (dd, J = 10.1, 1.8 Hz, 2H), 4.86 (t, J = 5.3 Hz, 1H), 4.41 (t, J = 5.9 Hz, 2H), 4.07-4.14 (m, 8H), 3.63 (q, J = 5.6 Hz, 2H), 1.72-1.80 (m, 4H), 1.59-1.68 (m, 4H), 1.37-1.49 (m, 8H).

Example 2D
Synthesis of compound 2D:
Synthesis of 1-cyclohexyl-1-quinoxalin-2-yl-hydrazine:
A microwave reactor was charged with 2-chloroquinoxaline (1.65 g, 10 mmol) and cyclohexylhydrazine hydrochloride (1.81 g, 12 mmol) in triethylamine (10 mL). The mixture was heated to 90° C. for 20 min in a microwave reactor. The reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with ethyl acetate. The organic phase was washed with water and brine, dried over anhydrous sodium sulfate and the solvent removed under reduced pressure. The residue was washed with hexane to give the title compound as a yellow solid (0.70 g, 29%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.98 (s, 1H), 7.86-7.89 (m, 1H), 7.65-7.68 (m, 1H), 7.53-7.57 (m, 1H), 7.35-7.39 (m, 1H), 4.46-4.53 (m, 1H), 3.85 (s, 2H), 1.88-1.92 (m, 2H), 1.64-1.81 (m, 5H), 1.45-1.56 (m, 2H), 1.14-1.26 (m, 1H)

Synthesis of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-[(E)-[cyclohexyl(quinoxalin-2-yl)hydrazono]methyl]-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (Compound 2D)
(±) 10-Camphorsulfonic acid (33 mg, 0.14 mmol) was added to a solution of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [3-formyl-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (0.97 g, 1.42 mmol), 1-cyclohexyl-1-quinoxalin-2-yl-hydrazine (0.36 g, 1.5 mmol), and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical (TEMPO-OH) (2 mg, 0.01 mmol) in anhydrous tetrahydrofuran (14 mL) under nitrogen atmosphere. The resulting solution was stirred at ambient temperature for 23 h. The reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with dichloromethane. The organic phase was washed with brine, dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure to give the title compound as a yellow solid (1.18 g, 91%) after recrystallization from dichloromethane/methanol.
¹ H-NMR (400 MHz, DMSO-d6) δ 9.34 (s, 1H), 8.26 (s, 1H), 8.17 (d, J = 6.9 Hz, 2H), 8.13 (d, J = 9.1 Hz, 2H), 8.01 (d, J = 2.7 Hz, 1H), 7.87 (d, J = 9.1 Hz, 1H), 7.69 (dd, J = 8.2, 1.4 Hz, 1H), 7.65 (td, J = 7.5, 1.4 Hz, 1H), 7.51-7.55 (m, 1H), 7.45 (d, J = 8.7 Hz, 1H), 7.38 (dd, J = 8.9, 3.0Hz, 1H), 7.13-7.15 (m, 2H), 7.11-7.12 (m, 2H), 6.32 (dd, J = 17.4, 1.8 Hz, 2H), 6.13-6.20 (m, 2H), 5.93 (dd, J = 10.3, 1.6 Hz, 2H), 4.86-4.94 (m, 1H), 4.07-4.13 (m, 8H), 2.15-2.25 (m, 2H), 1.72-1.79 (m, 4H), 1.61-1.68 (m, 8H), 1.37-1.50 (m, 9H), 1.21 (q, J = 13.0 Hz, 2H), 0.77 (m, 1H).

Example 2E
Synthesis of compound 2E:
Synthesis of 2,5-dihydroxy-4-methyl-benzaldehyde:
To a suspension of paraformaldehyde (2.1 g, 70 mmol), magnesium chloride (1.43 g, 15 mmol), triethylamine (5.6 mL, 40 mmol) in anhydrous acetonitrile (15 mL) was added methylhydroquinone (1.24 g, 10 mmol). The mixture was refluxed with stirring under nitrogen atmosphere for 17 h. The reaction mixture was cooled to ambient temperature, quenched with 1N aqueous HCl, extracted with ethyl acetate, and washed with brine. The organic layer was dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure. The residue was purified by flash column chromatography on silica gel with ethyl acetate/hexanes to give the title compound as a yellow solid (0.31 g, 20%).
^1H -NMR (400 MHz, MeOD) δ 9.85 (s, 1H), 6.95 (s, 1H), 6.70 (s, 1H), 2.21 (s, 3H).

Synthesis of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [2-formyl-5-methyl-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl]
To a solution of 4-(6-acryloyloxy-hex-1-yloxy)benzoic acid (2.19 g, 7.5 mmol) and 4-methoxyphenol (47 mg, 0.4 mmol) in anhydrous toluene (15 mL) and anhydrous dimethylformamide (DMF) (0.3 mL) was added oxalyl chloride (0.77 mL, 9 mmol) dropwise over 15 min at 45° C. After stirring for 19 h, the reaction mixture was cooled to ambient temperature and added dropwise over 20 min to a solution of building block K (0.51 g, 3.4 mmol) and N,N-dimethylcyclohexylamine (2.5 mL, 17 mmol) in anhydrous dimethylacetamide (11 mL) at 0-5° C. The reaction mixture was stirred at ambient temperature for 3 h. The reaction mixture was quenched by the addition of 1 M aqueous HCl and an ice-water bath, extracted with dichloromethane, washed successively with water, brine, dried over sodium sulfate and concentrated in vacuo. After recrystallization from dichloromethane/methanol, the title compound was obtained as a pink solid (1.38 g, 59%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 10.15 (s, 1H), 8.15-8.18 (m, 4H), 7.71 (s, 1H), 6.98-7.01 (m, 5H), 6.41 (dd, J = 17.4, 1.4 Hz, 2H), 6.13 (dd, J = 1 7.4, 10.5 Hz, 2H), 5.83 (dd, J = 10.3, 1.6 Hz, 2H), 4.15-4.21 (m, 8H), 4.07 (t, J = 5.9 Hz, 8H), 2.32 (s, 3H), 1.81-1.89 (m, 4H), 1.69-1. 77 (m, 4H), 1.48-1.54 (m, 8H).

Synthesis of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [5-methyl-2-[(E)-[methyl(quinoxalin-2-yl)hydrazono]methyl]-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (Compound 2E)
(±) 10-Camphorsulfonic acid (44 mg, 0.19 mmol) was added to a solution of 4-(6-prop-2-enoyloxyhexoxy)benzoic acid [2-formyl-5-methyl-4-[4-(6-prop-2-enoyloxyhexoxy)benzoyl]oxy-phenyl] (1.3 g, 1.9 mmol), 1-methyl-1-quinoxalin-2-yl-hydrazine (0.34 g, 2.0 mmol), and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical (TEMPO-OH) (4 mg, 0.02 mmol) in anhydrous tetrahydrofuran (20 mL) under nitrogen atmosphere. The resulting solution was stirred at ambient temperature for 22 h. The reaction mixture was quenched with a saturated aqueous solution of sodium bicarbonate and extracted with dichloromethane. The organic phase was washed with brine, dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure to give the title compound as a yellow solid (1.20 g, 75%) after recrystallization from dichloromethane/hexanes.
¹ H-NMR (400 MHz, DMSO-d6) δ 9.41 (s, 1H), 8.14-8.16 (m, 4H), 8.01 (s, 1H), 7.87-7.89 (m, 2H), 7.73-7.75 (m, 1H), 7.65-7.69 (m, 1H), 7. 49-7.53 (m, 1H), 7.34 (s, 1H), 7.11-7.15 (m, 4H), 6.32 (dd, J = 17.2, 1.6 Hz, 2H), 6.17 (dd, J = 17.4, 10.5 Hz, 2H), 5.93 (dd, J = 10.3, 1.6 Hz, 2H), 4.07-4.14 (m, 8H), 3.61 (s, 3H), 2.20 (s, 3H), 1.72-1.80 (m, 4H), 1.59-1.68 (m, 4H), 1.36-1.51 (m, 8H).

Example 3
The phase transition temperatures and mesophase textures were determined by differential scanning calorimetry and polarized light microscopy as described below using the compounds of Examples 1-2E and compared with compound R1 described in published patent WO2012/141245.

Polarized light microscopy:
Three milligrams of each compound was placed between two glass slides in a hot stage oven, heated from 25°C to 200°C, and then cooled again to 25°C. The characteristic birefringent texture was analyzed using a polarized light microscope. Glass substrates coated with a rubbed polyimide layer were also used to confirm the mesophase behavior of the compounds.

Differential Scanning Calorimetry:
Approximately 5 mg of each compound in a sealed aluminum pan was subjected to two successive heating-cooling cycles at a scan rate of 10° C./min. Transition temperatures were determined from the endothermic/exothermic peaks of the resulting DSC thermograms.

All phase transition results are summarized in Table 1. The state of the compound is indicated as "Cr" for solid crystalline phase, "N" for nematic, and "Iso" for isotropic liquid state.

Example 4
Preparation of Optical Films General Procedure for Preparation and Evaluation of LCP Coating Films on Rubbed Substrates 0.26 g of liquid crystal compound was dissolved in 830 μL of cyclopentanone. 13 μL of 1 wt% cyclopentanone solution of BYK361 was added, and the resulting solution was filtered through a 0.45 μm PTFE filter. 13 mg of Irgacure907 was added to obtain polymerizable compositions (1-2).

Each polymerizable composition was applied to a glass substrate coated with a rubbed polyimide layer (EHC). After drying/annealing the film for 4 minutes at the temperature indicated in Table 2, the film was photocured using a UV spot cure (Ushio SP-7) at a dose of 1000 mJ/ ^cm2 . UV exposure was performed at the temperature listed in Table 2.

Example 5
The retardation in the visible region (400-700 nm) was measured by the polarization rotation method using a polarizing microscope, a Senarmont compensator and an optical filter. The in-plane retardation _R0 can be calculated from the extinction position θ at a specific wavelength λ using the following equation:

The film thickness d is measured using a Bruker Dektak® stylus profiler. The birefringence Δn of the film is derived from the following equation: R ₀ =Δn.d

The results show that liquid crystal films were produced with increasing retardation relative to increasing wavelengths in the visible light range. The results are shown in Figure 1, where the wavelength dispersion of birefringence for Examples 1, 2, 2B and 2D is plotted.

Example 6
General procedure for preparation of LCP coating film on photoalignment layer for compounds R1, 1, 2, 2A, 2B, 2D and 2E:
Preparation of alignment layer using photoalignment material:
A glass substrate was spin-coated with a photoalignment composition (a photoalignment polymer at 2% solids in cyclopentanone as described in the application example on page 40 of published patent WO2012/085048). The film was dried at 80°C for 30 seconds, and the resulting film had a thickness of about 100 nm. The film was then exposed to aligning light, which was 500 mJ/ ^cm2 of parallel and linearly polarized UV (LPUV) light (280-320 nm). The polarization plane was at 0° with respect to a reference edge on the substrate.

Preparation of LCP formulations:
A 15.0 wt% solution of LCP was prepared by mixing 14.325 wt% LCP, 0.075 wt% inhibitor 2,6-di-tert-butyl-4-methylphenol (to prevent premature polymerization), 0.45 wt% photoinitiator Irgacure 369, and 0.15 wt% Tinuvin 123 in cyclohexanone and thoroughly stirred until the solids were completely dissolved at room temperature. The coating solution was applied onto a glass plate having the above alignment layer, and a liquid crystal film was formed by spin coating. After drying the film at the time and temperature shown in Table 3, the sample was cooled to room temperature. It was then photopolymerized by irradiating it with UV light (using a mercury lamp) at the approximate time and temperature shown in Table 3.

Example 7
The retardation of the film prepared in Example 6 was measured by ellipsometry. Figure 2 shows the retardation dispersion of the film prepared in Example 6.

The above results show that liquid crystal films prepared with the exemplified compounds exhibit increasing retardation with increasing wavelength in the visible light range.

Table 4 shows the values of Re ₄₅₀ /Re ₅₅₀ and Re ₆₅₀ /Re ₅₅₀ for each sample, where Re ₄₅₀ represents the retardation of the film at a wavelength of 450 nm, Re ₅₅₀ represents the retardation of the film at a wavelength of 550 nm, and Re ₆₅₀ represents the retardation of the film at a wavelength of 650 nm.

Table 4 shows the results of retardation properties of liquid crystal composition film. To improve color, it is preferable that Re ₆₅₀ /Re ₅₅₀ value is greater than 1.00 and less than 1.2. It is found that Re 650 /Re 550 of liquid crystal polymer film made with compound from Example 1, Example 2, Example 2A, Example 2B, Example 2D, Example _2E is significantly greater than Re ₆₅₀ /Re ₅₅₀ of liquid crystal composition of Comparative Example R1, and all Re ₆₅₀ /Re ₅₅₀ values are greater than _{1.01 and up to 1.09. Furthermore, Re 450 /} Re ₅₅₀ value less than 0.90 is preferable.

Example 8
A 30.0 wt% solution of compound 2B was prepared by mixing 22.635 wt% compound 2B, 0.015 wt% inhibitor 2,6-di-tert-butyl-4-methylphenol, 0.9 wt% photoinitiator Irgacure® Oxe 03 (BASF Corporation), 0.45 wt% Tego® flow 425, 6 wt% O1-(2-prop-2-enoyloxyethyl)pentanedioic acid O5-[4-[3-methyl-4-[4-[5-oxo-5-(2-prop-2-enoyloxyethoxy)pentanoyl]oxybenzoyl]oxy-phenoxy]carbonylphenyl] (LCP1, described in US Patent US2012114907) in cyclohexanone and thoroughly stirred until the solids were completely dissolved at room temperature. The film was prepared as described in Example 20 and dried on a temperature controlled hot plate at 97° C. for 2 minutes. The resulting film showed good alignment quality.

Example 9
A 30.0 wt% solution of compound 2B was prepared by mixing 25.635 wt% compound 2B, 0.015 wt% inhibitor 2,6-di-tert-butyl-4-methylphenol, 0.90 wt% Irgacure® Oxe03, 0.45 wt% Tego® flow 425, 3 wt% 6-(4-prop-2-enoyloxybutoxycarbonyloxy)naphthalene-2-carboxylic acid [4-[6-(4-prop-2-enoyloxybutoxycarbonyloxy)naphthalene-2-carbonyl]oxyphenyl] (LCP2, described in US 7,670,505 B2) in cyclohexanone and thoroughly stirred until the solids were completely dissolved at room temperature. A film was prepared as described in Example 20 and dried on a temperature controlled hot plate at 105°C for 2 minutes. The resulting film showed good alignment quality.

Example 10
The retardation of the samples described in Examples 8 and 9 was measured by an ellipsometer. Table 5 shows the results of the retardation properties of various films depending on the liquid crystal composition.

When using a liquid crystal composition, it was found that the films described in Examples 8 and 9 allow fine tuning of the retardation and obtaining _Re450 / _Re550 and _Re650 / _Re550 values as required by adjusting the ratio of various components of the liquid crystal composition.

Claims (13)

Formula (I):

[Wherein,
R ₁ , R ₂ and R ₃ are each independently selected from the group consisting of hydrogen, C ₁ -C ₁₂ straight or branched alkyl chain, C ₃ -C ₁₂ alkenyl, C ₁ -C ₁₂ alkoxy, C ₃ -C ₁₂ alkenyloxy, -(CH ₂ ) _m -C(CH ₃ ) ₃ , NO ₂ , CN, COR, -COOR, -OCOR, -CONR'R, -NR'COR, OCOOR, -OCONR'R, -NR'COOR, -F, -Cl, -CF ₃ and -OCF ₃ ;
Where:
m is an integer from 0 to 12;
R is selected from the group consisting of hydrogen, a C _1-18 alkyl group, a C _3-18 alkenyl group having a double bond at position 3 or higher, -(CH ₂ ) _p -C-(CF ₃ ) ₃ , CN, and an unsubstituted or substituted phenyl ring, where the substituents on the phenyl ring are selected from the group consisting of a C ₁ -C ₆ straight or branched alkyl chain, a C ₁ -C ₆ alkoxy, -C-(CH ₃ ) ₃ , halogen, -CF ₃ , NO ₂ , CN, COR''', -COOR'''', -OCOR'''', -CONR''R'''', -NR''COR'''', OCOOR'''', -OCONR''R'''', -NR''COOR'''', -F, -Cl, -CF ₃ , and -OCF ₃ ;
Where:
R″ is selected from the group consisting of hydrogen, a lower alkyl group, and a lower alkenyl group , the lower alkyl group being methyl, ethyl, propyl, butyl, pentyl, or hexyl, and the lower alkenyl group being 2-propenyl, 3-butenyl, 3-isopentenyl, 4-pentenyl, 5-hexenyl, or 4-isohexenyl ;
R''' is selected from the group consisting of hydrogen, a _C1-18 alkyl group, and a _C3-18 alkenyl group having a double bond at the 3rd or higher position;
p is an integer from 0 to 12;
R' is selected from the group consisting of hydrogen, lower alkyl, lower alkenyl and lower alkoxy , where lower alkyl is methyl, ethyl, propyl, butyl, pentyl or hexyl, lower alkenyl is 2-propenyl, 3-butenyl, 3-isopentenyl, 4-pentenyl, 5-hexenyl or 4-isohexenyl and lower alkoxy is methoxy, ethoxy, propoxy, butoxy, pentoxy or hexoxy ;
n is 0, 1, 2 or 3;
Y is selected from the group consisting of H or a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms;
Z is selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, where one or more carbon atoms may be replaced by -O-, -COO-, -OCO-, -OOC-, -O(CO)O-, -N-, -NR ^a -, -CON-, -CO-R ^b , -NH-R ^c , where R ^a is a C ₁ to C ₁₂ alkyl group, R ^b and R ^c are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or an organic group having 2 to 30 carbon atoms containing at least one aromatic ring, or a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms;
Rings C and D are, independently of each other, a phenyl ring or a cycloalkyl ring , provided that at least one of rings C or D is a phenyl ring ;
Ring E is a phenyl ring ;
The substituent X ₁ is selected from the group consisting of C ₁ -C ₁₂ substituted or unsubstituted linear or branched alkyl chains and C 1 -C ₁₂ alkoxy, where one or more carbon atoms may be replaced by -O-, -COO-, -OOC-, -O(CO)O-; or the substituent X ₁ is selected from the group consisting of C ₁ -C 12 substituted or unsubstituted linear or branched alkyl chains and C 1 -C 12 alkoxy, where one or more carbon atoms may be replaced by -O-, -COO- , -OOC-, -O(CO)O-;

Represented by the group represented by:
The substituent X2 _is represented by the formula (II):

Represented by the group represented by:
wherein in the group of formula (II), n is an integer from 0 to 24, and in the -(CH2)n- moiety of formula (II) _, one _or more carbon atoms may be replaced by -O-, -COO- , -OOC-, -O(CO)O- ;
An anisotropic compound of formula (II) wherein the group PG represents a polymerizable group selected from the group consisting of C H ₂ ═CW—COO—; where W represents H, methyl, ethyl, propyl, butyl, pentyl or hexyl . 2. The anisotropic compound according to claim 1, wherein R ₁ , R ₂ and R ₃ are each independently selected from the group consisting of hydrogen, lower alkyl, lower alkenyl, lower alkoxy, lower alkenyloxy, -F , -C-(CH ₃ ) ₃ and -CF ₃ , wherein lower alkyl is methyl, ethyl, propyl, butyl, pentyl or hexyl, lower alkenyl is 2-propenyl, 3-butenyl, 3-isopentenyl, 4-pentenyl, 5-hexenyl or 4-isohexenyl, lower alkoxy is methoxy, ethoxy, propoxy, butoxy, pentoxy or hexoxy, and lower alkenyloxy is 2-propenyloxy, 3-butenyloxy, 4-pentenyloxy or 5-hexenyloxy. 3. The anisotropic compound according to claim 2, wherein R ₁ , R ₂ and R ₃ are each independently selected from the group consisting of methyl, methoxy, -F, -C-(CH ₃ ) ₃ and -CF ₃ . The anisotropic compound according to any one of claims 1 to 3, wherein both rings C and D are phenyl rings. When both rings C and D are phenyl rings , the groups of formula (II) representing _X1 and _X2 are each independently of one another represented by the following formula:

4. The compound according to claim 1 , wherein n is an integer from 0 to 24, and the corresponding methacrylates thereof. 6. An anisotropic compound according to any one of claims 1 to 5 , wherein Z is selected from the group consisting of hydrogen and substituted or unsubstituted alkyl groups having 1 to 12 carbon atoms. An anisotropic compound according to any one of claims 1 to 6 , wherein PG is selected from acrylates or methacrylates. An LCP mixture comprising an anisotropic compound of formula (I) according to any one of claims 1 to 7 . 9. The LCP mixture according to claim 8 in crosslinked or polymerized form. A method for producing an optical film comprising an anisotropic compound according to any one of claims 1 to 7 or an LCP mixture according to claim 8 or 9 by exposure to an aligning light. An optical film comprising an anisotropic compound of formula (I) according to any one of claims 1 to 7 or an LCP mixture according to claim 8 or 9 . Use of a compound according to any one of claims 1 to 7 or an LCP mixture according to claims 8 or 9 in the manufacture of optical or electro-optical devices. An optical or electro-optical device comprising a compound according to any one of claims 1 to 7 or an LCP mixture according to claim 8 or 9 .